Hydraulic torque relief mechanism



May 30, 1967 M. J. HUBER 3,321,355

HYDRAULIC TORQUE RELIEF MECHANISM Filed May 11, 1965 5 Sheets-Sheet 1 442f 4 4,2 34 Z5 Z7 .F/G. Z 33 25 INVENTOR MORT/MER J #055? BY 2mm Ow May30, 1967 M. J. HUBER 3,321,355

I HYDRAULIC TORQUE RELIEF MECHANISM Filed May 11, 1965 5 Sheets-Sheet 2INVENTOR MgT/MER J. HUBER ATTORNEY 0, 1967 M. J. HUBER 3,321,856

' HYDRAULIC TORQUE RELIEF MECHANISM I Filed May 11, 1965 5 Sheets-Sheet5 INVENTOR M RT/MER J. HUBER ATTORNEY United States Patent 3,321,856HYDRAULIC TORQUE RELIEF MECHANISM Mortimer J. Huber, St. Paul, Minn,assignor to Motion Products Manufacturing Company, Inc, Ramsey County,Minn., a corporation of Minnesota Filed May 11, 1965, Ser. No. 454,780 r8 Claims. (CI. 40-33) This invention relates to an improvement inhydraulic torque relief mechanism and deals particularly with a driveunit designed particularly for the use in driving rotary elements whichare subjected to varying pressures.

Rotary signs for advertising purposes are now commonly used. Many ofthese signs are supported for rotation about a vertical axis. Some ofthe signs may be viewed from various directions. For example, FillingStations which are located at the intersection of highways, often usesigns of this type which rotate relatively slowly but with sufficientspeed 'so that they can be viewed easily from any direction during somepart of their rotation. While not specifically limited to signs of thistype, the present hydraulic torque relief mechanism is designed toconnect a motor such as an electric motor which rotates at a constantspeed with a vertical shaft on which the rotary sign is mounted.

One of the difficulties which is often experienced with signs of thetype in question lies in the fact that the signs, being of considerablewidth and height, are subjected to severe pressures when acted upon bywinds of high velocity. While the motors which drive such signs areusually connected to the signs through a gear reduction unit which actsto rotate the sign at a small fraction of the speed of rotation of themotor, there is often sufficient force against the sign during some partof the rotation to place a severe strain upon the drive motor. As thesign rotates from a feathered position to a position broadside of thewind, there is a considerable leverage tending to stop the rotation ofthe sign until the time when it is at right angles to the direction ofthe wind. After passing this position, there is also a considerableforce multiplied by the leverage acting to continue the rotation of thesign until it is again aligned with the direction of the wind. Theseforces are extremely detrimental to the drive motor if the sign isdirectly connected. While the difficulty may be somewhat alleviated bythe use of slip clutches and the like, clutches of this type must bereplaced at short intervals due to wear, and often cause very erraticmovements of the sign itself.

Due to the fact that signs of the type in question usually work for manyhours each day, and in some instances work continuously, the gearreduction units which connect the drive motor to the sign usuallycomprise hollow housings containing the gears which are substantiallyfilled with lubricating oil to prevent excessive year. I have found thatif a simple hydraulic clutch is provided between the drive motor and thedrive shaft of the sign which is normally submerged in the lubricatingfiuid, much of the previous difliculties may be obviated. The type ofhydraulic clutch in question, may comprise a rotor having projectingvanes and which rotates within a stator having inwardly projecting vaneswhich terminate in close proximity to the rotor vanes. The casing whichencloses the rotor is apertured so that the housing is at all timessubmerged in fluid. As a result, the rotation of the rotor by the drivemotor may exert a tremendous hydraulic force against the stator, tendingto rotate the stator in unison with the rotor. At the same time, thereis no positive drive between the rotor and stator, and as a result, ifsufficient leverage is exerted upon the sign, the speed of rotation ofthe stator may be very materially reduced. As a matter of fact, if thesign is subjected to suificient wind pressure during its rotation, thestator may actually rotate in a reverse direction relative to the rotorwithout stressing the drive motor beyond its normal capacity.

A feature of the present invention resides in the provision of aconstruction of the type described in which the rotor is driven at thesame speed as the drive motor, and in which the vanes of the rotor aresufiiciently close to the vane-s of the stator so that the stator isnormally rotated at a speed almost equal to the speed of rotation of therotor. At the same time, there is sufficient clearance between the vanesof the two units so that slippage can occur under conditions of highstress.

A further feature of the present invention resides in the provision of aunit of the type described in which the rotor is provided with a seriesof angularly spaced vanes, the stator is provided with what is usually asimilar number of inwardly projecting vanes, in which the housing of thestator fits snugly about the: rotor. Angularly spaced apertures areprovided in the housing, but these apertures are angularly spaced adistance which is greater than the spacing between the vanes in both therotor and stator. As a result, there is a space between the apertureswhere the fluid driven by the rotor acts directly against the vanes ofthe stator tending to rotate the two parts in unison.

These and other objects and novel features of the present invention willbe more clearly and fully set forth in the following specification andclaims:

FIGURE 1 is a plan view of the lower portion of the gear housing withthe upper portion thereof removed, certain of the parallel shaft beingshown in section.

FIGURE 2 is a vertical section through the gear housing, the position ofthe section being indicated by the line 2-2 of FIGURE 1.

FIGURE 3 is a vertical sectional view through the gear housing, thesection being at right angles to the section shown in FIGURE 1, and theposition of the section being indicated by the line 3-3 of FIGURE 1.

FIGURE 4 is an enlarged vertical section through the hydraulic clutchunit forming a part of the drive mechanism, the position of the sectionbeing indicated by the lines 44 in FIG. 5.

FIGURE 5 is a top-plan view of the clutch unit illustrated in FIGURE 4.

FIGURE 6 is a horizontal sectional view through a hydraulic clutch unit,the position of the section being indicated by the line 6-6 of FIGURE 4.

FIGURE 7 is a diagrammatic elevational View of a sign, showing the drivemechanism connected thereto.

With reference first to FIGURE 7 of the drawings, the drive unit 8 isillustrated in general by the letter A, while the rotatably driven signis indicated in general by the letter B. The sign B rotates about thevertical axis 10. A supporting plate Ill is indicated on a horizontalplane beneath the sign, the mounting plate ill being supported by asuitable framework which is not illustrated in the drawings. A hearing12 is mounted upon the mounting plate 11 and supports a verticallyextending shaft which is arranged on the axis 10. The lower end of theshaft 13 is connected to a driven shaft 14 which projects from the driveunit A. A motor 15 is supported by the drive unit and acts throughsuitable means in the gear housing A to drive the driven shaft 13 andtherefore to rotate the sign B about its vertical axis.

As is indicated in FIGURES 2 and 3 of the drawings, the drive unit Aincludes an upper section 16 and a lower section 17. The upper section16 includes a generally fiat top panel or plate 19 and downwardly depending peripheral side walls 20. The lower section 17 includes a bottomplate or panel 21 to which is secured upwardly extending peripheral sidewalls 22. The side walls 20 and 22 of the two sections normally meet inedge abutting relation, and a gasket 23 extends therebetween to seal thetwo units together. The two sections are connected together by suitablemeans such as cap screws 24 extending through apertures in theperipheral walls of the upper section and threaded into internallythreaded apertures in the lower section.

The drive motor is secured to the bottom plate 21 of the lower section17 and includes a motor shaft 25 which extends through the bottom panel21 of the gear housing, and through a suitable bearing 26 and seal 27.The clutch unit which is indicated in general by the letter C is mountedupon the motor shaft 25 and acts through the hydraulic clutch C torotate a concentric pinion 29. As is indicated in FIGURE 1 of thedrawings, the pinion 29 is in mesh with a gear 30 mounted upon avertical shaft 31 which is shown as supported by suitable bearings 32and 33 in the top and bottom housing portions 16 and 17. A pinion 34 ismounted upon the shaft 31 and is in mesh with a gear 35 on a parallelvertical shaft 36 supported vertically in the housing by means ofbearings 37 and 39 best illustrated in FIGURE 3 of the drawings. Apinion 40 on the vertical shaft 36 is in mesh with a gear 41 mounted onthe drive 14. Thus, it will be seen that rotation of the motor shaft 25of the motor 15 acts through the gear train within the housing of thedrive unit A to drive the driven shaft 14 at a greatly reduced speed. Aswill be understood, the driven shaft 14 is coupled to the vertical shaft13 which drives the rotary sign B.

Due to the severe strain which is placed upon the shaft 14, this shaftis supported by a pair of spaced bearings 41 and 42 mounted in bearingcups 43 and 44 formed as a part of the upper and lower sections 16 and17 of the housing. Seals 45 and 46 are provided to protect the housingfrom leakage.

The hydraulic clutch unit is best illustrated in FIG- URES 4, 5, and 6of the drawings. This unit C includes a rotor 49 which is pinned orotherwise secured to the motor shaft 25 by means of a pin extendingdiametrically through the rotor 49 and shaft 25 through thediametrically extending aperture 51. As is indicated in FIGURE 6 of thedrawings, the rotor 49 is provided with a considerable number ofangularly spaced vanes 53 which are preferably evenly spaced. Rotationof the motor shaft 25 thus causes rotation of the rotor 49.

The stator of the clutch unit C is indicated in general by the numeral54. The stator includes a bottom plate 55 from which depends a hub 56which is lined by a suitable bearing 57. The bottom plate 55 fits snuglybeneath the rotor 49. The stator also includes a top closure plate 59which adjoins the upstanding peripheral walls 60 on the bottom plate 50by a rabbeted joint 61 to prevent leakage. A closure plate 59 is securedto the lower portion of the stator housing by means of cap screws 62 orby other suitable means.

The cover plate 59 is provided with an upwardly projecting hub 63 whichaccommodates a vertical shaft 64 which supports, or forms, the pinion29. The shaft 64 is secured for rotation with the hub 63 by means of thepin 65 or other suitable means. The lower end of the hub 63 is groovedas indicated at 66 to accommodate a bearing 67 encircling the reduceddiameter portion 69 of the motor shaft 25 to hold the shaft 64 and motorshaft 25 :in alignment.

A cylindrical flange 70 extends upwardly from the top closure plate 59,and a series of angular spaced apertures 71 extend through the topclosure plate above the vanes of the rotor 49. Similar angularly spacedapertures 72 are provided through the bottom plate 55 inwardly of thecylindrical flange 73.

Due to the fact that the clutch unit C is constantly submerged inlubricating oil, rotation of the rotor 49 tends to cause the rotation ofthe stator unit 54 in unison therewith. The apertures 72 and 71 areangularly spaced .a distance in excess of the angular distance betweenthe radially extending vanes 53 of the rotor 49 which increases thetendency for the stator to rotate in unison with the rotor. However, ifthere is sufficient wind acting upon the sign B, the rotary movement ofthe sign may be slowed down, halted, or the sign may actually reverse indirection until the wind pressure abates and permits the continuedrotation of the sign.

There is a similar force which tends to retard the rotation of the signwhen the wind forces thereupon tend to rotate it faster than ispermitted by the motor. As a result, if sufficient wind is exertedagainst the sign, it may rotate the sign toward feathered positionduring gusts of wind of high velocity. When the gusts of wind abate, thesign can then continue its normal rotation.

In accordance with the patent statutes, the principles of constructionand operation of this improved hy-, draulic torque relief mechanism havebeen described, and while an endeavor has been made to set forth thebest embodiment thereof, it should be understood that changes may bemade within the scope of the following claims without departing from thespirit of the invention.

I claim:

1. A hydraulic torque relief mechanism including:

a hollow gear housing,

a motor secured to said housing and including a drive shaft extendinginto the interior thereof,

an externally vaned rotor secured to said drive shaft,

an internally vaned stator enclosing said rotor and including aplurality of angularly spaced apertures adjoining said rotor,

a driven shaft extending from said housing,

gear reduction means connecting said stator to said driven shaft,

said gear housing including lubricating fluid to a level above the levelof said stator,

whereby rotation of said rotor by said motor will transfer rotary forcethrough said fluid to said stator and through said gear reduction meansto said driven shaft.

2. A hydraulic torque relief mechanism including a hollow gear housing,

a drive shaft extending into said housing,

a driven shaft extending from said housing,

a hydraulic clutch connected between said drive shaft and said drivenshaft,

said clutch including an externally vaned rotor and a stator,

said stator including a pair of discs on opposite sides of said rotorand a peripheral wall connecting said discs and including inwardlyextending stator vanes extending into close proximity with said rotor,

at least one of said discs including a plurality of angularly spacedapertures adjoining the vanes of said rotor,

said housing being filled with hydraulic fluid to a level about saidhydraulic clutch,

whereby rotation of said drive shaft will act through the fluid in saidstator to drive said driven shaft.

3. The structure of claim 2 and including a gear reduction train betweensaid hydraulic clutch and said driven shaft.

4. A rotatable sign including:

a gear housing including a hollow body,

a drive shaft extending into said body,

a vertical driven shaft extending from said body,

a sign body including a vertical shaft connected to' said driven shaftand with which said sign body rotates,

a hydraulic clutch connected between said drive shaft and said drivenshaft in said gear housing,

said clutch including an externally vaned rotor connected to one of saiddrive and driven shafts,

a stator housing including an internally vaned housing enclosing saidrotor and connected to the other of said drive and driven shafts,

said stator housing having apertures therethrough outwardly of saidrotor, and

said gear housing including hydraulic fluid to a level above saidclutch.

5. The structure of claim 4 and including a gear reduction trainconnecting said stator housing to said driven shaft.

6. The structure of claim 4 and in which said stator includes a pair ofspaced discs and an internally vaned peripheral rotor encircling ringconnecting said discs,

said apertures extending through at least one said disc.

7 The structure of claim 6 and in which said apertures extend throughboth said discs.

8. The structure of claim 4 and in which said apertures are in angularlyspaced relation about the axis of said rotor and are spaced apart adistance greater than the angular distance between said vanes of saidrotor.

References Cited UNITED STATES PATENTS EUGENE R. CAPOZIO, PrimalExaminer. W. GRIEB, Assistant Examiner.

4. A ROTATABLE SIGN INCLUDING: A GEAR HOUSING INCLUDING A HOLLOW BODY, ADRIVE SHAFT EXTENDING INTO SAID BODY, A VERTICAL DRIVEN SHAFT EXTENDINGFROM SAID BODY, A SIGN BODY INCLUDING A VERTICAL SHAFT CONNECTED TO SAIDDRIVEN SHAFT AND WITH WHICH SAID SIGN BODY ROTATES, A HYDRAULIC CLUTCHCONNECTED BETWEEN SAID DRIVE SHAFT AND SAID DRIVEN SHAFT IN SAID GEARHOUSING, SAID CLUTCH INCLUDING AN EXTERNALLY VANED ROTOR CONNECTED TOONE OF SAID DRIVE AND DRIVEN SHAFTS, A STATOR HOUSING INCLUDING ANINTERNALLY VANED HOUSING ENCLOSING SAID ROTOR AND CONNECTED TO THE OTHEROF SAID DRIVE AND DRIVEN SHAFTS, SAID STATOR HOUSING HAVING APERTURESTHERETHROUGH OUTWARDLY OF SAID ROTOR, AND SAID GEAR HOUSING INCLUDINGHYDRAULIC FLUID TO A LEVEL ABOVE SAID CLUTCH.